Stellar bow shock

. A crescent-shaped bow shock is formed when the material in
the fast wind from the bright, very young star, LL Ori (center) collides with the slow-moving gas in its vicinity, coming
from the lower right. The stellar wind is a stream of charged particles moving
rapidly outward from the star. It is a less energetic version of the solar
wind that flows from the Sun. A second, fainter bow shock can be seen around a
star near the upper right-hand corner of this image, taken from the Hubble Space Telescope. Both stars are
located in the Orion Nebula; an intense star-forming region located about 1,500
light-years from the Earth. (Courtesy of NASA, the Hubble Heritage Team,
STScI, and AURA.)